What is a regrouping?

Regrouping is exchanging between place-value columns when adding or subtracting. In addition, ten ones are regrouped into one ten and 'carried' to the next column. In subtraction, one ten is regrouped into ten ones and 'borrowed' so there's enough to subtract.

Examples

• 47 + 8: 7+8=15, write 5 and carry 1 ten.
• 52 − 7: borrow a ten so 12 − 7 = 5.

Quick facts

• 'Carrying' and 'borrowing' are older names for regrouping.
• It only makes sense once place value is secure.